Process of treating copper ores



OFFIQE NIELS C. CI-IBISTENSEN, DE SALT LAKE GITY, UTAH.

PBQCESS 3F TREATING COPPER ORE-S.

N 0 Drawing.

iation oi? Ol'flCllZGfl ores of copper (or sum: ores which have been roasted.) wlth an S0 solution or to liriviation pronzesse in which {it}, is used in precipitating copper solutions ant. more especially to the recovery of the copper from these solutions. The intention relates parti. ilarly to the precipitation of the copper from the copper sullite solution or 'lt'rom solutions containing: cop per sulfate. 7

The lixiviation of the ore to secure the copper in solution as a copper sultite is described in niyll. Patent 21])DllC2ll3lOllS lilo. 118,156, No. No. semis, so that it is not necessary to describe this part of the process in detail. except to repeat here that the ore should be lixiviated with a cold concentrated S0 solution free from soluble sulfates, and that this operation should preferably be carried out by agitating the ore with the SO, solution. After the copper has been dissolved the pregnant solution should be separated from the lixiviated ore and the precipitation carried out without bringino; the solution into contact with air. Precaution should be taken to prevent the introduction of SO, and sulfates into the solution or the oxidation of the sulfites in solution to sulfates if complete precipitation is to be secured and loss of S0 avoided.

The object of my intention is to precipitate the copper from the SU solution asa cupro-cupric sulfite without the formation of copper sulfate and without he ting the solution or driving off the ex ess SG As described in my U. S. patent application No. I can accomplish the precipitation of the copper as cupro-cupric sulfite by adding copper to the copper sulfite solution and heating the solution and drivino; oil the excess S0 When the pre ipitation is brought about in this manner other sulfites such as Cast), which mav be in solution are also precipitated with the copper. The heating of the solution to drive off the G, and the absorption of the E50 to form a pecification of Letters Patent.

Application filed ilepteinber 30, 1919.

Patented Nov. 9, 1920.

Serial No. 327,404.

concentrated 30, solution to lixiviate more ore, are also steps which it is desirable to avoid, both because of saving in operating expense and in equipment.

As described in my ll. S. patent application No. 287,51? ,the copper may be precipitated from the sullite solution Without heating by the addition of Cu O but by this method all the S0 is also removed and the impurities such as CaSO etc, are precipitated with the copper.

It is the object of this invention to secure the precipitation of the copper from the cold S0 solution without removing; the excess S9 from the solution and' without precipitating the impurities such as CaS'O with the cupro-cupric sulfite. I bring; about this result by addin finely divided metallic copper to the cold S9,, solution containing the copper in solution and agitating the so.- lution so as to keep the copper in suspens on and bring all the solution into contact with the copper. The copper in solution is precipitated as cupro-cupric sulfite by the ac.- tion of the metallic copper as shown below:

2CuSO +Cu Cri,,SG .CiiSO lfany copper is present as sulfate in the solution it may be precipitated as a cupro-cupric sulfite by adding lime, calcium carbonate, or calc um suliite to the 530 solution and then adding the metallic copper. he lime or lime-stone dissolves in the SO, solution to Form calcium bisulfite which reacts with the CuSDL to givellatllh and @1130, in solution and the (31130 is then precipitated as cupro-"upric sulfite.

l he reactions are indicated below:

fl z e 3) CuSD -Hla (1150 CuS0,-l-CaSO PH SO The reac In all cases an excess of copper over the theoretical amount must be used as the action coats the copper particles and prevents the inside of the particles coming in contact with the copper solution. The finer the cop per the smaller the amount required and the quicker the action.

The finely divided copper for the precipitation is secured by roasting the cupro-cupric sulfite precipitate without access of air and in the presence of the excess of metallic copper from the precipitating operation, and reducing the cuprous oXid thus formed to metallic copper bv a suitable reducing agent,

as indicated below:

CufiQLluSQ-l-Cu:2Cu 0+2SO V C11 O+C= Cu+CO Cu O+H :2Cu+l-l This gives the copper in the very finely divided form which is best suited to the process.

The roasting and reducing operations are very simple and require but a short time and relatively low temperature on account of the fine subdivision of the precipitate.

The precipitation otthe copper from the cold S9 solution without removing the S0 thereby precipitating the copper as a cuprocupric sullite. V

2. The process of precipitating copper from an S9 solution which consists in mining finely divided metallic copper with solution and thereby precipitating the cop per as a cupro-cupric sulfite. I

3. The process of precipitating the copper present as a sulfate in an S0 solution which consists in adding to said solution a lime compound which will form a soluble suliite in said solution and adding metallic copper to said solution and thereby precipitating the copper as a cupro-cupric suliite.

i. The process of precipitatingthe copper present as a sulfate in an S0 solution which consists in adding to said solution a lime compound which will form a soluble suhitein said solutionyand adding finely divided metallic copper to said solution, thereby precipitating the copper as cupro-cupric sultits. 7

5. The process of precipitating the copper from a copper sulfate solution which consists in adding' $0 to said solution, adding to said solution a lime compound which. will form a soluble suliite in said solution, and adding metallic copper to said solution and ther by precipitating the copper as a cupr'o-cupric suliite.

6. The process of precipitating the copp from a copper sulfate solution which consists'in adding SCgto said solutioiu adding to said solution a lime compound which will form soluble sullite in said solution, and mixing finely divided metallic copper with said solution and thereby precipitating the copper as a cupro-cupric In testimony whereof i have signed my name to this specification.

NIELS o. onnis'rnusnn. 

